Systems and methods for using an electric motor in predictive and automatic engine stop-start systems

ABSTRACT

In some embodiments of the present disclosure, sensors mounted on a vehicle can allow opportunities for coasting to be predicted based on environmental conditions, route planning information, and/or vehicle-to-vehicle or vehicle-to-infrastructure signaling. In some embodiments of the present disclosure, these sensors can also predict a need for power and/or an end of a coast opportunity. These predictions can allow the vehicle to automatically enter a coasting state, and can predictively re-engage the engine and/or powertrain in order to make power available with no delay when desired by the operator.

CROSS-REFERENCE(S) TO RELATED APPLICATION(S)

This application is a continuation-in-part of U.S. application Ser. No.15/716,315, filed Sep. 26, 2017, the entire disclosure of which ishereby incorporated by reference herein for all purposes.

SUMMARY

This summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This summary is not intended to identify key features ofthe claimed subject matter, nor is it intended to be used as an aid indetermining the scope of the claimed subject matter.

In some embodiments, a vehicle is provided comprising an internalcombustion engine, an electric motor, an accessory drive, one or morevehicle state sensors, one or more environmental sensors, and a vehicleelectronic control unit (VECU). The accessory drive has a drive shaftand an output shaft. The drive shaft of the accessory drive is coupledto an output of the internal combustion engine, and the output shaft ofthe accessory drive is coupled to the electric motor. The one or morevehicle state sensors are configured to generate vehicle state signals.The one or more environmental sensors are configured to generateenvironment signals. The VECU is configured to, in response todetermining that a set of conditions for stopping the engine are met,transmit a signal to cause the internal combustion engine to be stopped;monitor the environment signals and the vehicle state signals to predicta time when engine power will be needed; and transmit a signal based onthe predicted time when engine power will be needed to the electricmotor to cause the electric motor to provide power to restart theinternal combustion engine through the accessory drive.

In some embodiments, a method of stopping and restarting an internalcombustion engine of a vehicle is provided. A vehicle electronic controlunit (VECU) monitors environment signals from one or more environmentalsensors of the vehicle and vehicle state signals from one or morevehicle state sensors of the vehicle. In response to determining thatthe environment signals and the vehicle state signals indicate a set ofconditions for stopping the internal combustion engine are met, the VECUtransmits a signal to cause the internal combustion engine to stop. TheVECU monitors the environment signals and the vehicle state signals topredict a time when power will be needed from the internal combustionengine. The VECU transmits a signal to an electric motor coupled to anaccessory drive to cause the electric motor to restart the internalcombustion engine based on the predicted time when power will be needed.

In some embodiments, a non-transitory computer-readable medium havingcomputer-executable instructions stored thereon is provided. Theinstructions, in response to execution by a vehicle electronic controlunit (VECU) of a vehicle having an internal combustion engine, cause theVECU to perform actions comprising monitoring environment signals fromone or more environmental sensors of the vehicle and vehicle statesignals from one or more vehicle state sensors of the vehicle; inresponse to determining that the environment signals and the vehiclestate signals indicate a set of conditions for stopping the internalcombustion engine are met, transmitting a signal to cause the internalcombustion engine to stop; monitoring the environment signals and thevehicle state signals to predict a time when power will be needed fromthe internal combustion engine; and transmitting a signal to an electricmotor coupled to an accessory drive to cause the electric motor torestart the internal combustion engine based on the predicted time whenpower will be needed.

DESCRIPTION OF THE DRAWINGS

The foregoing aspects and many of the attendant advantages of thisinvention will become more readily appreciated as the same become betterunderstood by reference to the following detailed description, whentaken in conjunction with the accompanying drawings, wherein:

FIG. 1 is a schematic diagram that illustrates an example embodiment ofa vehicle approaching a traffic control signal according to variousaspects of the present disclosure;

FIG. 2 is a schematic diagram that illustrates another exampleembodiment of a vehicle approaching a combination of obstacles accordingto various aspects of the present disclosure;

FIG. 3 is a chart that illustrates an example embodiment of variation inengine speed and vehicle speed over time according to various aspects ofthe present disclosure;

FIG. 4 is a block diagram that illustrates an example embodiment of avehicle according to various aspects of the present disclosure; and

FIGS. 5A-5B are a flowchart that illustrates an example embodiment of amethod of controlling an operating state of an engine of a vehicleaccording to various aspects of the present disclosure.

DETAILED DESCRIPTION

In general, while operating internal combustion engines, efficienciessuch as lower fuel consumption and reduced emissions can be gained byreducing engine speed. Engine speed can be reduced by disconnecting thedrivetrain and running the engine at idle in situations where enginepower is not needed to accelerate the vehicle. Efficiencies can also begained by shutting the engine down completely. These efficiencies can beimproved beyond what can be obtained by manual operation by taking intoaccount sensor information that is not available to the operator topredict additional opportunities for both engine-on coasting andengine-off coasting/stopping.

In some embodiments of the present disclosure, sensors mounted on avehicle can allow opportunities for coasting to be predicted based onenvironmental conditions, route planning information, and/orvehicle-to-vehicle or vehicle-to-infrastructure signaling. In someembodiments of the present disclosure, these sensors can also predict aneed for power and/or an end of a coast opportunity. These predictionscan allow the vehicle to automatically enter a coasting state, and canpredictively re-engage the engine and/or powertrain in order to makepower available with no delay when desired by the operator.

FIG. 1 is a schematic diagram that illustrates an example embodiment ofa vehicle approaching a traffic control signal according to variousaspects of the present disclosure. As illustrated, the vehicle istraveling towards the traffic control signal. If the vehicle will needto stop at the traffic control signal, then the vehicle has anopportunity to coast to a stop. Depending on the state of the vehicle, avariety of different coasting techniques could be used. For example, ifthe vehicle is traveling at a high rate of speed and needs to applyadditional braking power to come to a stop at the traffic controlsignal, the transmission may stay engaged in order to use engine drag tohelp slow the vehicle. If the vehicle is traveling at a lower rate ofspeed where engine braking would not be helpful, then the transmissionmay be disengaged in order to run the engine at a more efficient idlespeed while the vehicle is decelerating. If the vehicle is traveling ata rate of speed that indicates that it will be decelerating for a longtime, or if it can be determined that the vehicle will be stopped at thetraffic control signal for a long period of time, the engine of thevehicle may be shut down in order to achieve even lower fuel consumptionand lower emissions.

As illustrated, the traffic control signal may transmit wireless signalsthat indicate information regarding the state of the traffic controlsignal. The wireless signals may indicate signal phase and timing (SPAT)information as part of a vehicle-to-infrastructure (V2I) communicationnetwork. The vehicle can use these wireless signals to predict whetherit will be able to travel through the traffic control signal withoutstopping, or whether a stop will be required. If the vehicle determinesthat a stop will be required, the vehicle can then determine whetherentering a coast mode would be beneficial. The wireless signals may alsobe used to determine when to exit the coast mode.

Of course, traffic control signals are not the only unpredictableobstacle that will cause a vehicle to have to stop. FIG. 2 is aschematic diagram that illustrates another example embodiment of avehicle approaching a combination of obstacles according to variousaspects of the present disclosure. While the vehicle in FIG. 2 is stillapproaching a traffic control signal, it is also following a leadvehicle. The travel of the vehicle will be impacted by the travel of thelead vehicle as well. For example, if the lead vehicle slows down or isstopped at the traffic control signal, the vehicle will have to wait forthe lead vehicle to proceed regardless of the state of the trafficcontrol signal. In some embodiments, the vehicle may processvehicle-to-vehicle (V2V) wireless messages from the lead vehicle todetermine the size, position, speed, heading, acceleration, and brakesystem status of the lead vehicle. In some embodiments, the vehicle maydetermine relative speed, range, size, and other aspects of the leadvehicle using other environmental sensors of the vehicle, as describedfurther below. The vehicle may then use the combination of informationfrom the traffic control signal and the lead vehicle to determine whento enter and exit a coasting state.

FIG. 3 is a chart that illustrates an example embodiment of variation inengine speed and vehicle speed over time according to various aspects ofthe present disclosure. In the illustrated chart, time progresses alongthe X-axis, and engine speed and vehicle speed are indicated on theY-axis. To begin, the vehicle is cruising, with vehicle speed 302 andengine speed 303 remaining constant. At point 305, the engine speedbegins to drop, as does vehicle speed at point 304. This may be due toan operator of the vehicle releasing an accelerator pedal, applying abrake, disengaging a transmission, or via any other suitable technique.The speed may begin to drop due to a manual action taken by theoperator, or may occur automatically in response to determinations madebased on the vehicle environment. For example, the vehicle may determinebased on a predicted path and SPAT information received from a trafficcontrol signal that the vehicle will need to stop at the traffic controlsignal. Based on this prediction at point 305, the engine speed beginsto approach an idle speed, and at point 304 the vehicle speed begins tofall.

At point 307, the vehicle may predict that the vehicle will be stoppedfor a long enough time for it to be more efficient to shut down theengine. Accordingly, at point 307, the vehicle begins to shut down theengine, and at point 309, the engine is in a stopped state. The vehiclespeed continues to fall during region 306, as the vehicle coasts to astop at point 308.

The vehicle then monitors the environmental conditions to predict whenthe engine should be restarted. For example, the vehicle may receive aSPAT signal from the traffic control signal indicating a future timewhen the signal will change, or a V2V signal from a lead vehicleindicating that a brake has been released and the lead vehicle ispreparing to accelerate. The vehicle will then begin to restart theengine at point 311, in an attempt to have the engine fully restarted bypoint 313 when power is desired. In embodiments where information fromthe environmental sensors can allow the vehicle to predict a future timeat which engine power will be needed, the point 311 when the restartprocess is started can be chosen such that the engine will be fullyfinished restarting at substantially the same time that power isdesired, even if the restart process takes a significant amount of time.At point 313, the operator may request power to accelerate the vehicle,and the vehicle speed therefore begins to rise at point 314. The vehiclespeed 316 and engine speed 317 then rise together as during normaloperation.

In some embodiments, instead of or in addition to a traditional startermotor, the vehicle may include a higher-powered electric motor. Whereasa traditional starter motor may be capable of driving the internalcombustion engine of the vehicle to about 300 RPM, a higher-poweredelectric motor may be capable of driving the internal combustion engineof the vehicle to about 600 RPM or 700 RPM, and may do so faster thanthe traditional starter motor. Because the electric motor may be able torestart the internal combustion engine faster than the traditionalstarter motor, such embodiments of the vehicle may be able to wait untilpoint 315 to begin starting the internal combustion engine. Due to theelectric motor starting the internal combustion engine faster, theengine can still be fully restarted by point 313, even though therestart process waited until point 315 to commence.

FIG. 4 is a block diagram that illustrates an example embodiment of avehicle according to various aspects of the present disclosure. In someembodiments, the vehicle 400 is a Class 8 truck, though in someembodiments other types vehicles could be used. As illustrated, thevehicle 400 includes an internal combustion engine 434, an accessorydrive 436, and an electric motor 438. The internal combustion engine 434is the main power source for the vehicle 400, and is coupled to thepowertrain (not illustrated).

The accessory drive 436 is coupled to an output of the internalcombustion engine 434 in any suitable manner, including but not limitedto being coupled via a gearbox to a crankshaft of the internalcombustion engine 434, and being coupled to an accessory drive connectorof a transmission that is in turn connected to the internal combustionengine 434. Two non-limiting types of accessory drives 436 are powertake off (PTO) devices and front end accessory drive (FEAD) devices. Inembodiments of the present disclosure, the accessory drive 436 iscapable of bidirectionally transferring power to and from the internalcombustion engine 434. In other words, the accessory drive 436 mayreceive power from the internal combustion engine 434 in order to powera downstream device, or may provide power to the internal combustionengine 43 from a downstream device in order to turn the internalcombustion engine 434.

The electric motor 438 is coupled to the accessory drive 436, and to abattery (not illustrated). The electric motor 438 is configured to, atappropriate times, provide power through the accessory drive 436 to theinternal combustion engine 434. This power can be used to start (orrestart) the internal combustion engine 434, as described below. Theelectric motor 438 may also be able to, at appropriate times, receivepower from the accessory drive 436 to charge the battery. In someembodiments, the electric motor 438 is of an appropriate size and ratingto be able to turn the internal combustion engine 434 to a speed in arange of about 600-700 RPM.

Further implementation details and use of each of these components 434,436, 438 are, in general, known to one of ordinary skill in the art, andso are not described in further detail herein.

As illustrated, the vehicle 400 also includes a set of vehicle statesensors 414, a set of environmental sensors 404, and a vehicleelectronic control unit (VECU) 402. The vehicle 400 also includes otherelements that are known to one of ordinary skill in the art, includingbut not limited to a transmission and a communication bus such as a CANbus that allows communication between components of the vehicle 400.Because these elements are well known, they are not illustrated ordescribed further herein for the sake of brevity.

In some embodiments, the vehicle state sensors 414 monitor conditions ofvarious components of the vehicle 400 itself. As illustrated, thevehicle state sensors 414 include a coolant temperature sensor 432, anengine speed sensor 430, a battery sensor 428, a driveline state sensor426, a vehicle speed sensor 424, an accelerator sensor 422, a brakesensor 420, a clutch sensor 418, and a vehicle weight sensor 416. Thoughparticular vehicle state sensors 414 are described herein, thedescription should not be seen as limiting. One of ordinary skill in theart will understand that any other type of sensor that providesinformation about the vehicle 400 may be used as a vehicle state sensor414. In some embodiments, some of the illustrated vehicle state sensors414 may be omitted from the vehicle 400.

In some embodiments, the fluid temperature sensor 432 is configured todetermine the temperature of a fluid used within the vehicle 400. Forexample, an oil temperature sensor may determine a temperature oflubricating oil used by the engine. As another example, a coolanttemperature sensor may determine a temperature of a coolant circulatedthrough the engine and a radiator in order to control the temperature ofthe engine. As yet another example, a urea temperature sensor maydetermine a temperature of urea used to treat an exhaust of the vehicle.In some embodiments, other fluid temperature sensors 432 may be present.In some embodiments, more than one fluid temperature sensor 432 may bepresent, for measuring temperature of more than one type of fluid.

In some embodiments, the engine speed sensor 430 is configured todetermine a rotational (or other) speed at which the engine isoperating. In some embodiments, values produced by the engine speedsensor 430 may be provided to other components of the vehicle 400 by anengine electronic control unit (ECU). In some embodiments, the enginespeed sensor 430 may include an encoder or other device that physicallymeasures the speed of an output shaft of the engine.

In some embodiments, the battery sensor 428 is configured to measure alevel of charge of a battery of the vehicle 400. One or more batteriesmay be present in the vehicle 400, and each battery may be associatedwith a separate battery sensor 428. In some embodiments, the battery maybe used to provide power to a starter motor, and/or may be used toprovide power to other vehicle systems (including but not limited topower steering, power brakes, electrical systems, and HVAC systems)while the engine is not running.

In some embodiments, the driveline state sensor 426 is configured tomonitor a state of the driveline. For example, the driveline statesensor 426 may detect whether a clutch of the vehicle 400 is engaged ordisengaged. As another example, the driveline state sensor 426 maydetermine a gear ratio being used by a transmission of the vehicle 400.In some embodiments, the driveline state sensor 426 may detect thesestates as reported by the relevant components (e.g., a clutchengaged/disengaged signal reported by the clutch, or a gear ratioreported by the transmission). In some embodiments, the driveline statesensor 426 may derive these states by comparing an output shaft speed ofthe engine to an output shaft speed of the transmission.

In some embodiments, the vehicle speed sensor 424 is configured todetermine a speed at which the vehicle 400 is traveling along the road.The vehicle speed sensor 424 may use any suitable technique fordetermining vehicle speed. For example, the vehicle speed sensor 424 maydetect a speed reported by a wheel speed sensor to determine the vehiclespeed. As another example, the vehicle speed sensor 424 may use a speedreported by a traction control system or anti-lock braking system. Asyet another example, the vehicle speed sensor 424 may derive the speedat which the vehicle 400 is traveling along the road from other signals,such as by using the engine speed and the gear ratio, or by usinglocations reported by the GPS sensor 408.

In some embodiments, the accelerator sensor 422 is configured to detecta position of an accelerator pedal and to generate a signal indicatingthe position of the accelerator pedal. In some embodiments, theaccelerator sensor 422 may convert the position of the accelerator pedalinto a torque request and may provide a signal indicating the amount oftorque requested by the operator via the pedal.

In some embodiments, the brake sensor 420 is configured to detect aposition of a brake pedal and to generate a signal indicating theposition of the brake pedal. In some embodiments, instead of directlymeasuring the position of the brake pedal, the brake sensor 420 maydetect an amount of braking force being applied by friction brakesand/or any other braking mechanisms including but not limited tomagnetic brakes, retarders, exhaust brakes, and engine brakes.

In some embodiments, the clutch sensor 418 is configured to detect astate of a clutch of the transmission, and to generate a signalindicating whether the clutch is engaged or disengaged. In someembodiments, the clutch sensor 418 may sense the state of the clutchdirectly from the components of the clutch using a physical sensor. Insome embodiments, the clutch sensor 418 may derive the state of theclutch based on a speed of an output shaft of the engine and a speed ofan output shaft of the transmission.

In some embodiments, the vehicle weight sensor 416 is configured todetermine a weight of the vehicle 400, and to generate a signalindicating the determined weight. In some embodiments, the vehicleweight sensor 416 may detect an amount of stress on a vehicle component,including but not limited to a wheel, an axle, a suspension component,or a fifth-wheel coupling, and may derive the weight of the vehicle 400from the information obtained. In some embodiments, the vehicle weightsensor 416 may derive a weight of the vehicle based on otherinformation, including but not limited to an amount of torque beingproduced by the engine, a transmission gear ratio, and a resultingvehicle speed. In some embodiments, the vehicle weight sensor 416 maydetect a weight value that is wirelessly transmitted to the vehicle 400by an external scale. In some embodiments, the vehicle weight sensor 416may retrieve a weight value that is manually entered by the operator ofthe vehicle 400.

In some embodiments, the environmental sensors 404 monitor conditionssurrounding the vehicle 400 that may impact the vehicle 400 or itsperformance. As illustrated, the environmental sensors 404 include avehicle-to-vehicle (V2V) wireless interface 412, avehicle-to-infrastructure (V2I) wireless interface 410, a globalpositioning system (GPS) sensor 408, and one or more object detectionsensors 406. Though particular environmental sensors 404 are describedabove, the description should not be seen as limiting. One of ordinaryskill in the art will understand that any other type of sensor thatprovides information about the environment around the vehicle 400 may beused as an environmental sensor 404. In some embodiments, one or more ofthe environmental sensors 404 may be omitted from the vehicle 400.

In some embodiments, the vehicle-to-vehicle (V2V) wireless interface 412is configured to receive wireless communication signals from othervehicles, and may also be configured to transmit wireless communicationsignals to other vehicles. In some embodiments, the V2V wirelessinterface 412 may include a transceiver configured to receive dedicatedshort-range communications (DSRC) signals from other vehicles. In someembodiments, these signals may be within the 5.9 GHz spectrum. In someembodiments, the V2V signals received by the V2V wireless interface 412may include basic safety messages (BSMs) that provide vehicle dynamicsinformation including one or more of a heading, a speed, a location, anda braking status of a transmitting vehicle. In some embodiments, the V2Vwireless interface 412 may be configured to receive or transmitinformation from or to other vehicles via some other spectrum ornetworking technique, including but not limited to Wi-Fi, 4G, LTE, andsatellite communications.

In some embodiments, the V2I wireless interface 410 is configured toreceive wireless communication signals from infrastructure equipment,and may also be configured to transmit wireless communication signals toinfrastructure equipment. In some embodiments, the V2I wirelessinterface 410 may operate using similar techniques as the V2V wirelessinterface 412, including receiving DSRC signals from infrastructureequipment within the 5.9 GHz spectrum. In some embodiments, theinfrastructure equipment may include equipment associated with trafficcontrol devices, and the wireless communication signals received by theV2I wireless interface 410 may include signal phase and timing (SPaT)information that provides information regarding when and for how longthe traffic control signal will be in a given state (e.g., “the signalwill be red for ten more seconds”). In some embodiments, the V2Iwireless interface 410 may be configured to transmit information aboutthe vehicle 400 to infrastructure equipment to enable functionality suchas eco-freight signal priority. In some embodiments, the V2I wirelessinterface 410 may be configured to receive or transmit information fromor to infrastructure devices via some other spectrum or networkingtechnique, including but not limited to Wi-Fi, 4G, LTE, and satellitecommunications.

In some embodiments, the GPS sensor 408 is configured to receive signalsfrom GPS satellites, and to determine a position of the vehicle 400based on the signals. In some embodiments, the GPS sensor 408 may becapable of using other positioning technologies instead of or inaddition to satellite communication, including but not limited to usingcellular signal transmissions, using Wi-Fi signals, and using WiMAXsignals.

In some embodiments, the object detection sensors 406 are configured todetect objects near the vehicle 400. Any type of sensor that can detectobjects may be used.

One example of an object detection sensor 406 is a LIDAR sensor thatuses a laser to scan an area around the vehicle 400 and build athree-dimensional representation of any objects within the area. Anotherexample of an object detection sensor 406 is one or more video camerascoupled to a computer vision system that is configured to detect objectswithin the video data generated by the video cameras. Yet anotherexample of an object detection sensor 406 is a radar or ultrasonicsensor, which may be more suitable for detecting objects within closerange of the vehicle 400 than a LIDAR sensor or a video camera sensor.In some embodiments, other types of devices may be used as objectdetection sensors 406.

In some embodiments, the vehicle electronic control unit (VECU) 402 isan ECU computing device that is configured to receive signals from thevehicle state sensors 414 and the environmental sensors 404, todetermine an appropriate state for the transmission and the engine basedon the received signals, and to transmit control signals to an engineECU and a transmission ECU in order to place the transmission and enginein the appropriate state. Further details of the actions performed bythe VECU 402 and the determinations made by the VECU 402 are providedbelow.

The various electronic components illustrated in FIG. 4 may communicatewith each other through a vehicle-wide communications network (notshown). Those skilled in the art and others will recognize that thevehicle-wide communications network may be implemented using any numberof different communication protocols such as, but not limited to,Society of Automotive Engineers' (“SAE”) J1587, SAE J1922, SAE J1939,SAE J1708, and combinations thereof.

FIGS. 5A-5B are a flowchart that illustrates an example embodiment of amethod of controlling an operating state of an engine of a vehicleaccording to various aspects of the present disclosure. From a startblock, the method 500 proceeds to block 502, where a vehicle electroniccontrol unit (VECU) 402 of the vehicle 400 receives environment signalsfrom one or more environmental sensors 404 of the vehicle 400. At block504, the VECU 402 processes the environment signals to detect apredicted coast opportunity.

In some embodiments, a predicted coast opportunity is a state wherein itis predicted that the vehicle 400 will not be supplying forward power tothe drivetrain. This may be because the vehicle 400 is predicted to slowdown, is predicted to stop, or is predicted to maintain speed withoutengine power (such as while traversing a downhill grade). The VECU 402may examine any type of signal produced by the environmental sensors 404in order to predict that the vehicle 400 will slow down, stop, ormaintain speed without engine power for any reason.

As one example, the VECU 402 may receive a signal from the V2V wirelessinterface 412 that indicates that the vehicle 400 is likely to have toslow down or stop. For example, the V2V wireless interface 412 mayreceive a wireless transmission from a lead vehicle in front of thevehicle 400, wherein the wireless transmission indicates that the leadvehicle is applying brakes, is slowing down, or will otherwise become anobstacle in front of the vehicle 400. The VECU 402 may then determine,based on a range between the vehicle 400 and the lead vehicle along withthe information received in the wireless transmission, how much thevehicle 400 will have to slow down (or where the vehicle 400 will haveto stop), and may use that determination to detect a predicted coastopportunity.

As another example, the VECU 402 may receive a signal from the V2Iwireless interface 410 that indicates the vehicle 400 should slow downor stop. For example, a transmitter associated with a traffic controlsignal may send a wireless transmission indicating a state of thetraffic control signal, including but not limited to the current state,a future state, and/or how long the current state and/or future statewill remain active. The VECU 402 may use this information, along withthe distance between the vehicle 400 and the point where it would haveto stop, to determine whether a predicted coast opportunity exists. Ifthe VECU 402 determines that the vehicle 400 will have to stop at thetraffic control signal based on the signal timing and the currentvehicle speed, then it is likely that a predicted coast opportunityexists. The VECU 402 may also determine that a predicted coastopportunity exists if, by reducing vehicle speed, the vehicle 400 willreach the traffic control signal at a point when the vehicle 400 willnot have to stop. As another example, the V2I wireless interface 410 mayreceive a wireless transmission that indicates a speed at which thevehicle 400 may travel in order to increase the likelihood of reachingthe traffic control signal at a time when it will not cause the vehicle400 to stop, in which case a predicted coast opportunity may bedetermined in order to lower the vehicle speed to the speed indicated bythe wireless signal. The wireless transmissions may also indicatewhether the traffic control signal timing may be altered by a signalfrom the V2I wireless interface 410, such as is used to provideeco-freight signal priority, and the VECU 402 may take the availabilityof eco-freight signal priority into account when determining whether apredicted coast opportunity is present.

As another example, the VECU 402 may receive a signal from the GPSsensor 408 that indicates that the vehicle 400 is likely to have to slowdown, stop, or will otherwise not need the engine to power the vehicle400 to maintain speed. For example, the GPS sensor 408 may transmit asignal that, along with a predicted vehicle path from the GPS sensor 408or other component, indicates that the vehicle 400 is approaching a turnor a curve in the road for which the vehicle 400 will need to reduce itsspeed in order to successfully navigate the turn or curve, or a stopsign or railroad crossing at which the vehicle 400 should stop. Asanother example, the GPS sensor 408 may transmit a signal that, alongwith a predicted vehicle path from the GPS sensor 408 or othercomponent, indicates that the vehicle 400 will be traversing asufficient downhill grade to maintain the speed of the vehicle 400without power being supplied from the engine. As still another example,the GPS sensor 408 may transmit a signal that, along with a predictedvehicle path from the GPS sensor 408 or other component, indicates thatthe vehicle 400 will be approaching a stretch of road with a lower speedlimit than the current stretch of road, and that the vehicle 400 willtherefore have to slow down to remain in compliance. In someembodiments, other information may be obtained from the GPS sensor 408that can be used by the VECU 402 to determine that the vehicle 400 islikely to slow down or stop.

As another example, the VECU 402 may receive a signal from an objectdetection sensor 406 that indicates that the vehicle 400 is likely tohave to slow down or stop due to an obstruction in the roadway. Forexample, a LIDAR, radar, ultrasonic sensor, or a computer vision systemmay detect a pedestrian, a rock, a stopped vehicle, or another objectwithin the roadway and the potential path of the vehicle 400. This maycommonly occur at intersections, where an object detection sensor 406may either detect a lead vehicle stopped in front of the vehicle 400(and so the vehicle 400 would have to stop regardless of the state ofthe traffic control signal), or vehicles or pedestrians that constitutecrossing traffic (and so the vehicle 400 would have to stop to avoid acollision).

As still another example, the VECU 402 may determine a predicted coastopportunity is present using a combination of signals from theenvironmental sensors 404. As one non-limiting example, the VECU 402 mayreceive signal timing information via the V2I wireless interface 410,and may combine the signal timing information with information from theobject detection sensors 406 and/or V2V wireless interface 412 todetermine how long it will take after the traffic control signal changesfor the lead vehicles to clear the intersection before the vehicle 400can proceed. As another non-limiting example, the VECU 402 may use apredicted path and location from the GPS sensor 408 along with objectinformation from the object detection sensor 406 to determine whether adetected object will actually be within the predicted path of thevehicle 400, or whether the detected object can be ignored.

Next, at decision block 506, a determination is made regarding whether aset of coast conditions are met based on the environment signals. Insome embodiments, any opportunity for the vehicle 400 to travel withoutforward power being applied by the engine may be considered as meetingthe set of coast conditions. In some embodiments, the VECU 402 may checka coast condition related to how long the coast opportunity is predictedto persist. As an example, this coast condition may be met if the coastopportunity is predicted to persist for a long enough time for theengine to be completely shut down and restarted before power is againneeded. As another example, this coast condition may be met if the coastopportunity is predicted to persist for a long enough time for theengine to be shut down for long enough such that the fuel savings andemissions reductions gained for doing so outbalance a drop in fuelefficiency and/or emissions cleanliness during the startup and shutdownprocess. In some embodiments, checking a coast condition may includedetermining how quickly the vehicle 400 is likely to decelerate, and maybe met if engine drag or engine braking force does not need to be usedto provide the predicted deceleration. In some embodiments, checking acoast condition may include checking signals from the V2V wirelessinterface 412 or the V2I wireless interface 410 to determine whether anysignals report that an emergency vehicle is approaching, and the coastcondition may not be met if any emergency vehicles are approaching.

If the set of coast conditions are met, then the result of decisionblock 506 is YES, and the method 500 proceeds to block 508. Otherwise,if one or more of the coast conditions are not met, then the result ofdecision block 506 is NO, and the method 500 returns to block 502 toreceive more environment signals and to detect a subsequent predictedcoast opportunity.

At block 508, the VECU 402 transmits a signal to cause a powertrain ofthe vehicle 400 to be opened. In some embodiments, the signaltransmitted by the VECU 402 may be sent to the transmission ortransmission controller, and may cause the transmission to automaticallydisengage its clutch or to automatically shift the transmission intoneutral, thus automatically entering the coasting state. In someembodiments, the signal transmitted by the VECU 402 may cause a coastinstruction or indicator to be presented to an operator of the vehicle400 in order to cause the operator to manually disengage the clutch orshift the transmission into neutral. Once the powertrain is opened, thevehicle 400 is in an “engine-on” coasting state.

At block 510, the VECU 402 receives vehicle state signals from one ormore vehicle state sensors 414 of the vehicle 400. The vehicle statesignals allow the VECU 402 to determine whether the vehicle 400 is in astate in which the engine may be shut down in order to enter an“engine-off” coasting state. At block 512, the VECU 402 processes thevehicle state signals to check a set of conditions for stopping theengine. For example, a fluid temperature sensor 432 such as an oiltemperature sensor may provide a signal indicating an oil temperature.It may be desirable to keep the engine running until the oil temperaturereaches an optimum temperature range. As such, a condition for stoppingthe engine may be that the oil temperature (as reported by the fluidtemperature sensor 432) is within the optimum temperature range. Asanother example, a battery sensor 428 may report a state of charge of abattery. Because the battery may be used to power vehicle systems whenthe engine is off (or power the electric motor 438), and the engine isused to charge the battery, a condition for stopping the engine may bethat the state of charge of the battery is greater than a thresholdamount of charge, given an expected load to be placed on the battery anda duration for which the load will be applied. As still another example,the vehicle speed sensor 424 may report a vehicle speed value, and shutdown may be limited to situations where the vehicle speed value is belowa high speed threshold. Likewise, the engine speed sensor 430 may reportan engine speed value, and shut down may be limited to situations wherethe engine speed value is below an engine speed threshold. Yet anotherexample, which is not illustrated in FIG. 4, is a back pressure ortemperature sensor that detects when an after-treatment regenerationsystem should be activated. Because the engine is used in theregeneration process, a condition for stopping the engine may be thatthe sensors do not indicate a need for regeneration.

The method 500 then proceeds to a continuation terminal (“terminal B”),and from terminal B (FIG. 5B) to decision block 514, where adetermination is made regarding whether the engine should be stopped.This determination is based on the set of conditions checked in block512. Typically, the determination is based on whether or not all of theconditions in the set of conditions are met. In some embodiments, thedetermination may be based on whether one or more of the conditions inthe set of conditions are met. If the determination is made that theengine should be stopped, then the result of decision block 514 is YES,and the method 500 proceeds to block 516, where the VECU 402 transmits asignal to cause the engine to stop. The signal may be transmitted by theVECU 402 to an engine ECU or other device responsible for controllingoperation of the engine. In some embodiments, the signal may set atorque target or an engine speed target of zero in order to cause theengine to stop. In some embodiments, the signal may be a shutdowncommand that initiates the shutdown process. In some embodiments, thesignal may cause a decompression device to be activated in order toreduce engine vibration during shutdown and to reduce load on thestarter during restart. Use of a decompression device is described incommonly owned, co-pending U.S. application Ser. No. 15/341,320, filedNov. 2, 2016, the entire disclosure of which is hereby incorporated byreference for all purposes.

The method 500 then proceeds to a continuation terminal (“terminal C”).Otherwise, if the determination is made that the engine should not bestopped, then the result of decision block 514 is NO, and the method 500proceeds directly to terminal C. From terminal C, the method 500proceeds to block 518, where the VECU 402 receives one or more signalsfrom the environmental sensors 404 and/or the vehicle state sensors 414to detect a restart state.

In some embodiments, the restart state may be a state wherein a vehiclestate sensor 414 detects that torque is requested from the engine,including but not limited to a signal from the accelerator sensor 422indicating that the accelerator has been pressed. In some embodiments,another type of control input from the operator, including but notlimited to wiggling the steering wheel, pressing a button on thedashboard, and shifting the transmission from neutral to a drive gear,may indicate the presence of a restart state. In some embodiments, arestart state may be detected when a vehicle state sensor 414 indicatesthat a coast condition is no longer valid. For example, if a coastcondition requires a minimum state of charge of the battery to bereported by the battery sensor 428 and a subsequent signal from thebattery sensor 428 indicates that the state of charge has fallen belowthis minimum amount, then a restart state may be detected. Likewise, ifa coast condition requires that a temperature reported by a fluidtemperature sensor 432 be maintained within an optimum range and thetemperature falls below that range, then a restart state may bedetected.

In some embodiments, the restart state may be a state wherein anenvironmental sensor 404 detects that the vehicle 400 should be able toaccelerate, either immediately or at a predicted point in the future.For example, the V2I wireless interface 410 may receive a wirelesstransmission from a traffic control signal that indicates that thetraffic control signal will allow the vehicle 400 to proceed in fiveseconds. The VECU 402 may use this information to determine that arestart state will be present five seconds in the future. The VECU 402may also determine that the restart state will be present sooner thanthe point indicated by the V2I wireless interface 410 by an amount oftime it will take the engine to restart so that power is available assoon as the restart state exists. For example, if it takes three secondsfor the engine to restart and the traffic control signal will change infive seconds, then the VECU 402 may determine that a restart state willbe present two seconds into the future. As another example, the VECU 402may receive a location signal from the GPS sensor 408 and determine thata curve along the projected path will be straightening out, a downhillgrade will be ending, a speed limit will be rising, or other pathconditions exist that will require engine power to accelerate thevehicle 400. As yet another example, the VECU 402 may receive a signalfrom the V2V wireless interface 412 indicating that a lead vehicle isaccelerating, from which the VECU 402 may determine that a restart stateis present because the lead vehicle will soon be out of the way. Asstill another example, the VECU 402 may receive a signal from the objectdetection sensors 406, and may determine that a restart state is presentbecause an obstacle in the roadway has been moved or cross traffic isclear.

At decision block 520, a determination is made regarding whether thesignals from the environmental sensors 404 and/or the vehicle statesensors 414 indicate a restart condition. If a restart condition exists,then the result of decision block 520 is YES, and the method 500proceeds to block 522. Otherwise, if a restart condition does not exist,then the result of decision block 520 is NO, and the method 500 returnsto terminal C to check again for a restart condition.

At block 522, if the engine is stopped, the VECU 402 transmits a signalto cause the engine to restart. The signal may be a command to restartthe engine, a torque request or an engine speed request that is greaterthan zero, a command to engage or disengage a decompression device, ormay be any other signal that causes the engine to restart. In someembodiments, the signal may be transmitted to the electric motor 438,which then applies torque to the internal combustion engine 434 via theaccessory drive 436, thereby restarting the internal combustion engine434.

At block 524, the VECU 402 transmits a signal to cause the powertrain tobe closed. In some embodiments, the signal is a command sent directly tothe transmission or transmission controller to cause the powertrain tobe closed. If the engine was running before block 522, then the overallactions of the process between block 508 and block 524 will be toautomatically open the powertrain to coast, and then to automaticallyclose the powertrain to stop coasting. In some embodiments, the signalcauses an indication to be presented to the operator of the vehicle 400to close the powertrain, and the operator may take actions accordingly.

In some embodiments, the signal at block 524 may not be transmitteddirectly after the engine is restarted at block 522. For example, coastconditions relating to a downhill grade, a stop, and/or the like maycontinue to be met while a restart state is detected related tosomething other than accelerating the vehicle 400, including but notlimited to a temperature threshold, a battery charge state, and aregeneration process. In such embodiments, the VECU 402 may not transmitthe signal that causes the powertrain to be closed until after a coastcondition relating to accelerating the vehicle is no longer met or theVECU 402 otherwise detects a demand for acceleration.

The method 500 then proceeds to an end block and terminates.

While illustrative embodiments have been illustrated and described, itwill be appreciated that various changes can be made therein withoutdeparting from the spirit and scope of the invention.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:
 1. A vehicle, comprising:an internal combustion engine; an electric motor; an accessory drivehaving a drive shaft and an output shaft, wherein the drive shaft of theaccessory drive is coupled to an output of the internal combustionengine, and the output shaft of the accessory drive is coupled to theelectric motor; one or more vehicle state sensors configured to generatevehicle state signals; one or more environmental sensors configured togenerate environment signals; and a vehicle electronic control unit(VECU); wherein the VECU is configured to: in response to determiningthat a set of conditions for stopping the engine are met, transmit asignal to cause the internal combustion engine to be stopped; monitorthe environment signals and the vehicle state signals to predict a timewhen engine power will be needed; and transmit a signal based on thepredicted time when engine power will be needed to the electric motor tocause the electric motor to provide power to restart the internalcombustion engine through the accessory drive.
 2. The vehicle of claim1, wherein the accessory drive is a front end accessory drive or a powertake-off.
 3. The vehicle of claim 1, wherein the environmental sensorsinclude one or more of a camera, a global positioning system (GPS)sensor, a LIDAR sensor, a radar sensor, a vehicle-to-vehicle (V2V)wireless interface, and a vehicle-to-infrastructure (V2I) wirelessinterface).
 4. The vehicle of claim 1, wherein the vehicle state sensorsinclude one or more of a coolant temperature sensor, an engine speedsensor, a battery sensor, a driveline state sensor, a vehicle speedsensor, and an accelerator sensor.
 5. The vehicle of claim 1, whereinthe signal to cause the engine to restart is based on the predicted timewhen engine power will be needed and a predicted amount of time thatrestart of the engine will take.
 6. The vehicle of claim 1, wherein theset of conditions for stopping the engine include a predicted stop ofthe vehicle at a traffic light for which a signal received by a V2Iwireless interface of the vehicle indicates will be red at a predictedarrival time of the vehicle, a predicted stop of the vehicle for anobject in the path of the vehicle, a predicted stop of the vehicle for arailroad crossing, a predicted stop of the vehicle for a predicted turnof the vehicle, a predicted stop of the vehicle at a stop sign, apredicted downhill grade, a predicted speed limit reduction, or apredicted road curve.
 7. The vehicle of claim 1, wherein determiningthat a set of conditions for stopping the engine are met includes:predicting a time period for which the engine will be stopped based on asignal received by a V2I wireless interface that indicates when atraffic light will change to allow the vehicle to proceed; and comparingthe time period to a threshold time period for which fuel savings fromshutdown outweigh a fuel cost of stopping and restarting the engine. 8.The vehicle of claim 1, wherein the set of conditions for stopping theengine of the vehicle includes one or more of: an engine coolanttemperature being between a low temperature threshold and a hightemperature threshold; a vehicle speed being below a high speedthreshold; an engine speed being below an engine speed threshold; abattery state of charge being above a battery charge threshold; and anafter-treatment regeneration system being inactive.
 9. The vehicle ofclaim 1, further comprising a decompression device, wherein the VECU isfurther configured to: in response to determining that the set ofconditions for stopping the engine are met, transmit a signal to causethe decompression device to be activated.
 10. A method of stopping andrestarting an internal combustion engine of a vehicle, the methodcomprising: monitoring, by a vehicle electronic control unit (VECU),environment signals from one or more environmental sensors of thevehicle and vehicle state signals from one or more vehicle state sensorsof the vehicle; in response to determining that the environment signalsand the vehicle state signals indicate a set of conditions for stoppingthe internal combustion engine are met, transmitting, by the VECU, asignal to cause the internal combustion engine to stop; monitoring, bythe VECU, the environment signals and the vehicle state signals topredict a time when power will be needed from the internal combustionengine; and transmitting, by the VECU, a signal to an electric motorcoupled to an accessory drive to cause the electric motor to restart theinternal combustion engine based on the predicted time when power willbe needed.
 11. The method of claim 10, wherein monitoring theenvironmental signals and the vehicle state signals to predict a timewhen power will be needed from the internal combustion engine includesreceiving, by a vehicle-to-infrastructure (V2I) wireless interface ofthe vehicle, a signal indicating a time when a traffic control signalwill change to allow the vehicle to proceed.
 12. The method of claim 11,wherein transmitting the signal to cause the engine to restart based onthe predicted time when engine power will be needed includestransmitting the signal to cause the engine to restart at a time that isearlier than the time when the traffic control signal will change by anamount of time that restart of the engine will take.
 13. The method ofclaim 10, wherein determining whether the environment signals and thevehicle state signals indicate a set of conditions for stopping theinternal combustion engine of the vehicle are met includes predicting atime period for which the engine will be stopped, and comparing the timeperiod to a threshold time period for which fuel savings from shutdownoutweigh a fuel cost of stopping and restarting the engine.
 14. Themethod of claim 13, wherein predicting a time period for which theengine will be stopped includes determining when a traffic controlsignal will change state to allow the vehicle to proceed based on asignal received by a V2I wireless interface.
 15. The method of claim 14,wherein predicting a time period for which the engine will be stoppedincludes predicting how long it will take one or more lead vehiclesbetween the vehicle and the traffic light to start moving after thetraffic light changes.
 16. The method of claim 10, wherein the set ofconditions for stopping the internal combustion engine of the vehicleincludes one or more of: an engine coolant temperature being between alow temperature threshold and a high temperature threshold; a vehiclespeed being below a high speed threshold; an engine speed being below anengine speed threshold; a battery state of charge being above a batterycharge threshold; and an after-treatment regeneration system beinginactive.
 17. The method of claim 10, further comprising, in response todetermining that the set of conditions for stopping the internalcombustion engine are met: transmitting, by the VECU, a signal to causea decompression device to be activated.
 18. A non-transitorycomputer-readable medium having computer-executable instructions storedthereon which, in response to execution by a vehicle electronic controlunit (VECU) of a vehicle having an internal combustion engine, cause theVECU to perform actions comprising: monitoring environment signals fromone or more environmental sensors of the vehicle and vehicle statesignals from one or more vehicle state sensors of the vehicle; inresponse to determining that the environment signals and the vehiclestate signals indicate a set of conditions for stopping the internalcombustion engine are met, transmitting a signal to cause the internalcombustion engine to stop; monitoring the environment signals and thevehicle state signals to predict a time when power will be needed fromthe internal combustion engine; and transmitting a signal to an electricmotor coupled to an accessory drive to cause the electric motor torestart the internal combustion engine based on the predicted time whenpower will be needed.
 19. The computer-readable medium of claim 18,wherein monitoring the environmental signals and the vehicle statesignals to predict a time when power will be needed from the internalcombustion engine includes receiving, by a vehicle-to-infrastructure(V2I) wireless interface of the vehicle, a signal indicating a time whena traffic control signal will change to allow the vehicle to proceed.20. The computer-readable medium of claim 19, wherein transmitting thesignal to cause the engine to restart based on the predicted time whenengine power will be needed includes transmitting the signal to causethe engine to restart at a time that is earlier than the time when thetraffic control signal will change by an amount of time that restart ofthe engine will take.